public function csvExport(array $extraFields = [])
{
$url = '/players/csv_export?app_id=' . $this->api->getConfig()->getApplicationId();
$headers = ['Authorization' => 'Basic ' . $this->api->getConfig()->getApplicationAuthKey()];
$body = ['extra_fields' => $extraFields];
return $this->api->request('POST', $url, $headers, json_encode($body));
}